What’s Vulnerable › Vulnerabilities

CVE-2026-29009: U-Boot < 2026.07-rc2 Buffer Overflow in nfs_readlink_reply() via NFS READLINK

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-08 · updated 2026-10-24
• Weakness: CWE-120

Description

U-Boot before 2026.07-rc2 contains a buffer overflow vulnerability in nfs_readlink_reply() (net/nfs-common.c) when CONFIG_CMD_NFS is enabled, allowing a malicious or compromised NFS server to overflow the 2048-byte nfs_path_buff buffer by returning multiple relative symlink targets that are appended without cumulative length validation. Attackers can send two or more READLINK responses containing relative symlink targets of approximately 1100 bytes each to corrupt adjacent BSS variables including nfs_server_ip, nfs_server_mount_port, nfs_server_port, nfs_our_port, nfs_state, and rpc_id, potentially achieving memory corruption and control over the NFS client state machine.

Affected products

• u-boot: before 2026.04; 2026.04-rc1, 2026.04-rc2, 2026.04-rc3 — fixed in 2026.04

How to fix

Upgrade to a fixed version: u-boot 2026.04. Check the vendor advisory for mitigations.

References

• https://git.u-boot-project.org/u-boot/u-boot/-/commit/d6694018eaddefac6aae974f9cec72fd6e58f1bc
• https://git.u-boot-project.org/u-boot/u-boot/-/releases/v2026.07-rc2
• https://lists.denx.de/pipermail/u-boot/2026-May/617853.html
• https://u-boot.org/
• https://www.vulncheck.com/advisories/u-boot-rc3-buffer-overflow-in-nfs-readlink-reply-via-nfs-readlink
• https://y637f9qq2x.com/posts/u-boot-tcp-nfs-vulns/

Get alerted when CVE-2026-29009 or the next vulnerability affects your stack